ATF inhibits acute R5 HIV-1 replication in MDMs. (A). The anti-HIV activity of uPA and ATF were tested on primary MDMs infected with an R5 HIV-1. The compounds were added to the cell cultures at the time of infection and every 3 days after infection. The results of a single experiment, representative of 5 independently performed experiments with cells from different donors, are shown. The error bars indicate the SD of triplicate samples, whereas asterisks at the indicated time points indicate statistical significance (P = .001) among Nil and uPA or ATF treated cells; no significant differences were observed in the inhibition levels induced by uPA or ATF. (B) Culture supernatants of uninfected MDMs and in vitro–infected MDMs (C) were analyzed for the levels of uPA and suPAR at the day corresponding to the peak of viral replication (RT activity) in 5 independent experiments performed with cells from different donors. Differences in the levels of suPAR, uPA, the uPA-suPAR complex, and the suPAR/uPA ratio between uninfected and infected cells tested were not significant. R²  was calculated by linear regression and P values by Spearman rank test. cpm indicates counts per minute.